He acknowledged having made two female congressional aides "uncomfortable" by asking them about surrogacy when he and his wife faced infertility.

The committee also said it would investigate Blake Farenthold, who used $84,000 (£62,000) of taxpayers' money to settle a sexual harassment lawsuit with his former spokeswoman.

Over in the Senate, Mr Franken told his colleagues on Thursday: "Today I am announcing that in the coming weeks I will be resigning as a member of the United States Senate.

"I may be resigning my seat but I am not giving up my voice."

The former Saturday Night Live comic and two-term senator has apologised to several women who have accused him of groping and sexual harassment, but he faced mounting pressure to step aside after a new allegation surfaced on Wednesday.

Democrats desert senator in grope claims

Mr Franken said some of the claims against him "are simply are not true", but added that women "deserve to be heard and their experiences taken seriously".

He also referenced the sexual misconduct allegations that have been levelled against President Donald Trump and Republican Alabama Senate candidate Roy Moore.

"I, of all people, am aware that there is some irony in the fact that I am leaving while a man who has bragged on tape about his history of sexual assault sits in the Oval Office, and a man who has repeatedly preyed on young girls campaigns for the Senate with the full support of his party."

Media playback is unsupported on your deviceMedia captionFranken accuser: I was disgusted

Mr Franken is not the only US politician to have found himself engulfed by sexual harassment in recent weeks.

On Tuesday, Michigan Democrat John Conyers announced he would resign amid claims of sexual harassment made by his congressional aides.